Conventionally, a large-scale integration (LSI) has been used in a computing processor, i.e., a processor such as what is called a central processing unit (CPU). Recently, an electric power consumption of the LSI has increased in response to an increase in performance and the like of the LSI, so that a total electric power amount, including an energy consumption due to a cooling in response to the increase in the electric power consumption of the LSI, to be consumed in an entirety of a system provided with a server having a lot of LSIs has become large.
Increased electric power consumption in a system comes not only to an environmental issue in terms of an energy saving but also to an issue of causing a necessity of expanding cooling equipment to cope with an increase in a heat generation in response to the increase in the electric power consumption and also of increasing a running cost of the system. These issues have become salient especially in a data center which includes several hundreds or more of such servers and supports an infrastructure in a society. Therefore, it has been of significance to take measures for reducing an electric power consumption of a server in response to requirements for promoting an energy saving and reducing a running cost.
Meanwhile, a technique of improving a processing ability of an information processing apparatus by making a plurality of computing processes cooperate to perform an information process has been used. For example, a computing processor (CPU), a storage device (memory), an input/output device (I/O device), and the like are collected as a processing unit (a system board) in a server apparatus, a plurality of processing units are operated at the same time to divide processes, and thereby a processing ability as a whole is improved.
However, a load in an information process is not constant and all CPUs, memories, and system boards are not necessarily required to operate at any time. When a plurality of system boards are in operation, electric power consumption increases for the operation. Therefore, an operation of a lot of system boards at a state with a relatively light load results in useless electric power consumption.
In response, a measure for reducing an electric power consumption has been taken conventionally in which a power supply to a circuit not in use is stopped in an inside of an LSI which is used as a computing processor. Besides, a technique of applying a dynamic fallback of hardware resources to reduce total electric power consumption has been considered based on a system performance and a resource specification condition. Detailed information of such techniques can be obtained in Japanese Laid-open Patent Publication No. H9-179667 and Japanese Laid-open Patent Publication No. 2003-316751.
However, an electric power reduction in an entirety of a server cannot be realized sufficiently in the configuration of reducing an electric power in an inside of an LSI, for example. In other words, since an electric power consumed by an LSI is a part of the electric power consumed in the entirety of the server, a process of saving electric power consumption in wider range has been sought.
Especially in the conventional technique, elements except for a processing ability such as an electric power used for operating a cabinet which houses a plurality of processing units and an electric power used for cooling the processing units and the cabinet have not been taken into consideration. Therefore, the electric power is consumed uselessly in the conventional technique and there is a problem of not being able to efficiently reduce the electric power consumption in the entirety of the system.